The number of internet users in South Africa has passed 5 million and continues to enjoy strong growth, research shows. But internet penetration in Africa's ­economic powerhouse is only 10%, still far behind developed countries in the west.

South Africa's internet users grew from 4.6 million to 5.3 million last year, a rise of 15%, according to research by World Wide Worx, a technology and research and strategy organisation, sponsored by Cisco.

Arthur Goldstuck, the managing director of World Wide Worx, said: "The good news is that we will continue to see strong growth in 2010, and we should reach the 6 million mark by the end of the year."

The climb follows years of stagnation between 2002 to 2007, when internet penetration in South Africa never rose above 7%. But the rate almost doubled in 2008, and continued accelerating in 2009.

World Wide Worx said the growth had been driven by regulatory changes enabling small internet providers to enter the market with more competitive packages. It cited the granting of electronic communications network service licences to more than 400 organisations.

"This meant that service providers that were previously required to buy their network access from one of the major providers could now build their own networks or choose where they wanted to buy their access," it said.

The Internet Access in South Africa 2010 study found that growth had been spurred by small and medium businesses upgrading from dial-up to broadband connections. In doing so, they extended internet access to general office staff, adding up to 20 new users each.

The laying of the $600m (£368m) Seacom undersea cable linking the South African coast with Europe is expected to increase the number of connections and make them faster.

Goldstuck added: "In the coming year operators will begin to leverage the combination of new undersea cable capacity and new fibre-optic networks to supply corporate clients and resellers with bigger, faster and more flexible capacity.

"Almost every large player in the communications industry has realigned its business to take advantage of this relentless change."

Consumer demand is also rising, driven partly by the popularity of social networking websites such as Facebook, Twitter and YouTube. In 2008 South Africa's online advertising grew by 32%, the steepest rise in the English-speaking world. But nine in 10 South Africans are still not online, with many in poor townships or rural areas relying on internet cafes or doing without.

South Africa ranks fourth in Africa for total internet connections behind Egypt, Nigeria and Morocco, according to Internet World Stats.

Figures from last September showed penetration in Africa at 6.8%, the lowest of any region in the world, despite growth of 1,392% in the past decade. North America stood at 74.2%, Australasia at 60.4%, Europe at 52%, Latin America at 30.5%, the Middle East at 28.3% and Asia at 19.4%.